Date code of Barnaul 14.5x114 Case

What is the year of manufacture for a Barnaul 14.5x114 Case headstamped (see below)?


Do the trtas have any meaning or are they just Soviet stars?

EDIT: I remembered asking a question ages ago about a 12.7x108 case with the cyrillic “D” date code and searched it. Here I found that “K” was 1956.